Objective To study the effect of extreme snowfall on soil respiration of plantations in north subtropics-warm temperate transition zone.

Method A controlled experiment including snow addition, natural snowfall and snow remove was conducted in a plantation after a heavy snowfall in January 2018 in Xinyang, He'nan Province. The soil respiration variations under different treatments were measured with LI-8100 in different snow cover depths. The soil temperature, soil moisture, microbial biomass carbon, microbial biomass nitrogen, and soil available nitrogen contents were detected to determine the relationships between soil respiration and environmental factors.

Result The results showed that the snow addition significantly elevated soil temperature in the earlier stage of the experiment. However, the soil temperature under snow addition treatment was significantly lower than that in the control during the middle and later stage, and across the whole experiment, respectively. Snow addition elevated the soil respiration rate by 21.57%, but snow remove did not affect the soil respiration. The change of snowfall did not affect the contents of microbial biomass carbon, microbial biomass nitrogen and soil available nitrogen. The elevated soil respiration was mainly ascribed to the elevation of soil temperature in the early stage of the experiment.

Conclusion Extreme snowfall may increase soil respiration rate in plantations in the climate transitional zone, but it is affected by snowfall. The snowfall with the depth of about 30 cm will not significantly affect soil respiration rate. If snow depth continues to increase, the soil carbon emission rate will increase. In addition, the impact of snow depth on soil respiration at different stages of snowmelt is not consistent, and the impact of snow on soil respiration mainly occurs before the snow melts completely. This study can provide partial data supporting the establishment of ecosystem carbon cycle model under climate change scenario.